Tissue poromechanical deformation effects on steam pop likelihood in 3-D radiofrequency cardiac ablation

Figures

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  Fig. 1. a Model geometry of close-irrigated ablation catheter, b Cross-section of contact between the electrode tip and cardiac tissue (dimensions data from manufacturer: tip electrode length is 4 mm, tip electrode size is 7 Fr (French scale or French gauge system, commonly used to measure the size of a catheter), and tip electrode diameter (= 2a) is 2.33 mm [35–39])

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  Fig. 2. A schematic of the 3-D Radiofrequency Cardiac Ablation (RFCA) procedure and the computational domain

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  Fig. 3. A detailed schematic of the RFCA computational model geometry and boundary conditions used for electrical, thermal, fluid flow, and deformation analysis

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  Fig. 4. Detailed boundary conditions for a voltage, b blood flow and thermal, and c poromechanical deformation

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  Fig. 5. Mesh convergence finite element numerical computation showing sufficient number of elements were used in the computation

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  Fig. 6. a Locations around the electrode within the cross-section, and b cross-section through the middle of electrode-tissue domain where computed variables are discussed

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  Fig. 7. Model validation showing good match between computed transient temperatures and experimental results of Jain and Wolf, 2000 [61]. Locations are those shown in Fig. 6

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  Fig. 8. Effect of thermally driven poromechanical deformation on computed temperature, pressure, and velocities, showing a small effect

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  Fig. 9. Impact of deformation on computed temperatures at the locations shown in Fig. 6. Percent difference is calculated as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\frac{{\mathrm{T}}_{\mathrm{deform}}-{\mathrm{T}}_{\mathrm{undeform}}}{{\mathrm{T}}_{\mathrm{undeform}}}(^\circ \mathrm{C})\times 100\mathrm{\%}$$\end{document}Tdeform-TundeformTundeform(∘C)×100%

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  Fig. 10. Effect of inclusion of poromechanical deformation on the expected region for steam pop (temperatures 99 °C or higher) in the cardiac tissue at different times during procedure

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  Fig. 11. Blood velocity magnitude a and convective heat flux b in the cardiac tissue for two different blood vessel diameters (representing two different porosities) after 60 s of heating. Poromechanical deformation is included here

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  Fig. 12. Transient temperatures at location B1 (Fig. 6a) of two different blood vessel diameters (representing two different porosities). Poromechanical deformation is included here